> The accountants I have had here have been completely unable to read basic investment account data. They have fabricated numbers out of thin air, repeatedly made the same mistakes over and over.

Were these independent accountants and not something like an HR Block? If so, I guess I'd look for recommendations and calling them ahead of time to see if they have experience with UK x US taxes. Unfortunate if that's been the case you've seen.

If it was something like a chain service, I've heard nothing but awful things about how they're essentially a keyboard proxy for entering your taxes into software without any understanding.